Classically, a cam follower comprises at least a tappet, a pin and a roller. The tappet extends along a longitudinal axis, while the pin and the roller are centered on a transverse axis. The tappet is formed with two lateral flanges, delimiting an intermediate gap between them and each comprising a cylindrical bore. The roller is positioned in the intermediate gap, between both flanges and bores. The pin is fitted in the two bores, such that the roller is movable in rotation relative to the pin around its axis. The pin may be caulked, in other words plastically deformed, on both opposite ends to create a mechanical connection by press-fit in the tappet bores.
When the cam follower is in service, the roller collaborates with a cam synchronized with the internal combustion engine camshaft. The rotation of the camshaft leads to a periodic displacement of a piston of the pump that rests against the tappet, to allow fuel to be delivered. The tappet is movable back and forth along the longitudinal axis, while the roller is movable in rotation around its central axis.
As shown by example in EP-A-2 607 636, it is known to provide the tappet with lubrication channels. Depending on the configuration and orientation of the cam follower, the oil lubricant flows freely or is projected via these channels toward the roller and the pin. The lubrication can be achieved simply by gravity when the roller is positioned downwards, but not when the roller is positioned upwards, relative to the tappet.